[Pharo-project] A ready only transcript does not fly

Fernando I think that we should rollback the transcript. because this is really annoying that we cannot use the transcript: copy and paste execute an expression there. May be this is better to improve the ThreadSafeTranscript. The new one looks like a regression and I'm quite sure people will not like it. So this was a good try but we should recognise when stuff do not work as good as we wanted. Stef